1. Field of the Invention
This invention relates to: a method of recognizing an image of a nozzle hole for picturing a nozzle hole in which a nozzle hole of a liquid droplet ejection head as represented by an ink jet head is pictured and is subjected to recognition by means of image and the like, and a method of correcting the position of the liquid droplet ejection head by using the same; a method of inspecting a nozzle hole; an apparatus for recognizing an image of a nozzle hole and an apparatus for ejecting a liquid droplet equipped with the same; a method of manufacturing an electro-optical device; an electro-optical device; and an electronic equipment.
2. Description of the Related Art
In a liquid droplet ejection apparatus which supplies a function liquid from a function liquid supply system to a liquid droplet ejection head mounted on a carriage, such as a color filter deposition apparatus to which an ink jet method is applied, the liquid droplet ejection head needs to be replaced, because the life of the liquid droplet ejection head itself becomes short depending on the properties of the function liquid and the like. However, when the liquid droplet ejection head is replaced, there is a limit of mechanical accuracy in stably maintaining high positional accuracy (attaching accuracy) of the liquid droplet ejection head relative to the carriage.
Therefore, conventionally, the following measure has been taken using a nozzle hole image recognition method, i.e., after a liquid droplet ejection head is attached to a carriage, nozzle holes are pictured by a recognition camera with a strobe, and the positions of the nozzle holes are recognized through the image and, finally, positional deviation of the liquid droplet ejection head is corrected on data. In this case, in consideration of accuracy, the liquid droplet ejection head is moved to a fixed position of a recognition camera through the carriage, and two outermost nozzle holes are imaged.
This kind of conventional method is used in a state in which the liquid droplet ejection head is not filled with the function liquid yet. The function liquid supply system is connected to the liquid droplet ejection head after data correction. In this case, however, a piping member is manually attached to an adapter of the liquid droplet ejection head. Therefore, there has been a possibility that the attaching position of the liquid droplet ejection head may slightly deviate. Thus, in reality, for example, an image recognition operation is conducted again for checking, and thus a series of replacement operations are complicated and is not swift enough.
Considering the above problems, it is originally preferred that the nozzle hole image recognition operation be conducted after the function liquid supply system is connected to the liquid droplet ejection head. However, in a state in which the liquid droplet ejection head is filled with the function liquid, projections and recesses of the meniscus surfaces of the nozzle holes (surfaces of the function liquid formed on the ejection side of the nozzle holes) become non-uniform due to inertia accompanied by the movement of the liquid droplet ejection head and pressure fluctuations within piping of the function liquid supply system. As a result, irregular irradiation occurs in the taken images, affecting accuracy of image recognition.